(1) Field of the Invention
This invention relates to fresh produce and more particularly to the transportation of said produce.
(2) Description of the Prior Art
Before this invention, fresh harvested produce such as radishes had been loaded into trailers and chilled by a water flood. The water was flooded into the trailer by inserting water pipes into the open doors of the trailer and leaving the doors open for the water to drain from the trailer after it had flushed the product. After the product was chilled, the normal atmosphere was purged from the trailer and from the produce by flooding the area with nitrogen gas as produced by liquid nitrogen. Thereafter the trailer was closed as tightly as possible and sent to its destination. During this time, conventional refrigeration units were provided to keep the contents as near as possible to 32.degree. Fahrenheit.
Before filing the parent application, a search was made in the United States Patent and Trademark Office and the following patents were found:
______________________________________ JOHNSON ET AL 2,479,840 ELLIS 3,153,917 SNELLING 3,385,073 LICHTENBERGER ET AL 3,421,336 MAURER 3,525,235 ______________________________________
JOHNSON ET AL discloses cooling a refrigerated car by the expanding of liquid air. As described in column 5, line 11 of that patent, the liquid air might contain more oxygen than the atmosphere itself, or it might contain less oxygen.
ELLIS discloses discharging liquid nitrogen below floorboards within a compartment. Fresh food within the compartment would be chilled, but not frozen.
SNELLING discloses a refrigeration system for shipping perishable commodities having a heat exchanger (evaporator) at the top of the compartment. The gaseous nitrogen is discharged to the outside of the compartment. SNELLING also discloses pulling outside air from outside of the compartment or container to within the compartment or container. Column 7, line 4 indicates that the nitrogen may be discharged within the container.
LICHTENBERGER ET AL discloses coolant conduits extending under a covered floor or channels in the floor.
It does not appear to applicant that MAURER is as significant as the above described patents.
During the prosecution of the parent application, applicant became aware of the DIXON patents. They are as follows:
______________________________________ DIXON 3,239,360 DIXON 3,269,133 DIXON 3,365,307 DIXON 3,487,769 DIXON 3,563,757 DIXON 3,962,477 ______________________________________
These patents show that it is desirable to reduce the amount of oxygen present in a closed container carrying fresh produce. The DIXON references teach that it is desirable not to reduce the oxygen below 5%. Specific examples in DIXON indicate that the oxygen in certain cases may be reduced to as low as 1/4 of 1%.
The following additional patents are of record in the parent application.
______________________________________ COYNER 2,751,882 STOWASSER ET AL 3,672,182 RHOAD 3,961,925 WATERS 4,229,948 SHAW 4,307,580 ______________________________________
However, applicant does not believe they are as pertinent as the patents specifically discussed above.